Solenoids are, of course, well known in the art. A typical design of solenoid has a plunger or movable armature of magnetic material which is slidingly received within a cylindrical guide tube. The guide tube is formed of non-magnetic material and has a stop or a stationary armature of magnetic material located at one end. A biasing member normally urges the plunger or movable armature away from the stop or stationary armature.
A solenoid coil surrounds the cylindrical guide tube and a housing of magnetic material around the solenoid coil comprises, together with the stop and the plunger, a magnetic circuit. When the solenoid coil is de-energized, the plunger is spaced away from the stop by a biasing member. When the solenoid coil is energized by an electric current, the magnetic flux engendered in the magnetic circuit causes the plunger to slide axially in the cylindrical guide tube until it reaches the stop. The axial movement of the plunger is normally extremely rapid and the plunger strikes the stop with considerable force. Upon de-energization of the solenoid coil, the plunger slides away from the stop due to the influence of the biasing member.
Various configurations of plunger rods have been developed which are attached to the plunger in order to transfer the axial movement of the plunger within the housing to an area outside of the housing. The end of the plunger rod within the housing is adapted to mate with the plunger and the end of the plunger rod which extends outside of the housing is adapted to interface with a component which is to be moved axially by the solenoid. In order to effectively move the component in an axial direction, the component which is being moved must be aligned with the longitudinal axis of the solenoid as the movement of the plunger rod of the solenoid will be along the axis of the solenoid. While some misalignment is allowed due to the design and manufacturing tolerance involved in the manufacturing of the various components, it is essential that the axis of the solenoid and component being moved longitudinally be aligned in order to eliminate any type of binding or sticking of the solenoid during its operation.
Accordingly, what is needed is a solenoid which will allow a substantial amount of misalignment between the axis of the solenoid and the axis of the movement of the component being moved by the solenoid in order to provide additional flexibility to the design engineer.